As defined in [1]} and [2]}, a canonical orthonormal tetrad \(e_\sigma ^{(\rho )}\)  that adds three unitary space-like vectors to the four-velocity vector \(e_\sigma ^{(0)}=V_\sigma \)  is
\(\nonumber e^{(1)}_\sigma =(0,B,0,0), \;\;\; e^{(2)}_\sigma =\left(0,0,\frac{\sqrt{B^2A^2r^2+G^2}}{A},0\right), \;\;\; e^{(3)}_\sigma =(0,0,0,C),\) 
